Editing Single system image (section)

===Single IPC space===
Some SSI systems allow processes on different nodes to communicate using [[inter-process communication]]s mechanisms as if they were running on the same machine.  On some SSI systems this can even include [[Shared memory (interprocess communication)|shared memory]] (can be emulated in software with [[distributed shared memory]]).

In most cases inter-node IPC will be slower than IPC on the same machine, possibly drastically slower for shared memory.  Some SSI clusters include special hardware to reduce this slowdown.